This project is part of a long-term collaborative effort between this laboratory and Dr. Shyh-Ching Lo's at AFIP to investigate the co-factors contributing to the pathogenesis of AIDS. It has been a fruitful scientific and intellectual collaboration. The laboratory continues to support work on diagnosis and characterization of mycoplasma originated from AIDS patients, sexually transmitted disease (STD) patients, and others. We applied serological tests that were developed in this laboratory to several clinical settings, including patients with HIV infection, non-gonococcal urethritis (NGU), STDs, and intravenous drug using. We found a high prevalence of antibodies to M. penetrans in patients with Kaposi's sarcoma and antibodies to M. genitalium in patients with NGU. Using paired donor-recipient specimens, we also found M.fermentens and M. genitalium were transmissible through blood transfusion. Recently, we were able to show that the association of antibody to M. genitalium with the sexual transmission of HIV was highly significant while other STDs were not significantly associated. In FY97, we were asked to provide serological tests on specimens from patients who suffered Gulf War syndrome. Over 6,000 paired specimens, including controls, were examined, and we were not able to find any difference between soldiers who served in the Gulf War and controls in antibodies to M.fermentens. Of future interest for mycoplasma study is the contribution of mycoplasma to neoplasms after long-term chronic infection. We have shown that some species of mycoplasma were able to transform cells in vitro after long-term co-cultivation, and several oncogenes were activated.